This study presents the nutrient data collected from women who were being screened for premenstrual syndrome (PMS) for entry into an intervention study. Screening was by the Steiner self-rated questionnaire. One hundred and forty-four overweight women completed the screening process and eighty-eight met the criteria for PMS. All women kept 4 d diet diaries pre- and postmenstrually over two menstrual cycles. The mean energy and macronutrient intakes were compared between the pre- and postmenstrual phases. Energy and macronutrient intake was also calculated according to food categories. Goldberg's cut-off limit for the ratio of energy intake to estimated basal metabolic rate was used to exclude data that was incompatible with predicted energy requirements. The diet diaries were also used to determine the mean number of meals or snacks eaten pre- and postmenstrually. Nutrient analysis of the diet diaries of the women with PMS showed a significant increase (P < 0.001) in total energy and all macronutrients premenstrually when compared to nutrient intake postmenstrually. Women who did not meet the criteria for PMS showed a significant increase in energy and fat intake (P < 0.05) but not in the other macronutrients. When adjusted for energy, data collected from women with PMS showed a premenstrual significant increase in fat, carbohydrate (P < 0.05) and simple sugars (P < 0.001). There was a significant decrease (P < 0.001) in protein premenstrually. Women not meeting the PMS criteria showed no significant difference between pre- and postmenstrual intakes when adjusted for energy. Analysis according to food categories in women with PMS showed a significantly greater intake premenstrually of energy and all macronutrients for cereals, cakes and desserts and high-sugar foods (P < 0.001). In women with PMS there was a significantly greater number of 'episodes of eating' premenstrually (P < 0.001). This study provides further evidence, to support the very limited number of earlier studies, that there is a group of women with PMS who increase their nutrient intake during the premenstrual phase. This could potentially be a contributing factor for some women experiencing difficulties adhering to suggested dietary modification and should be considered when counselling premenopausal women.